1. Field of the Invention
The present invention relates to a signal recording apparatus and method, a signal reproducing apparatus and method, a medium, and an information assembly.
2. Description of the Related Art
As the high efficient encoding system employing the VLC (Variable Length Coding) or DCT (Discrete Cosine Transform), the DVCPRO (trade name, defined in SMPTE314M as the compression method) or the MPEG (Moving Picture Experts Group) compression is provided, but the details of these compression methods are different. For example, in order to convert a DVCPRO bit stream into an MPEG bit stream, it was necessary that the DVCPRO bit stream is once uncompressed to restore the image data, which is then MPEG compressed again.
However, with the above method, since the DVCPRO bit stream is once uncompressed to restore the image data, which is then MPEG compressed again, the video signal is compressed twice, resulting in a problem that the image quality is degraded inevitably.
On the contrary, the present inventor proposed a conversion method which is able to convert a bit stream subjected to the DVCPRO compression to an MPEG bit stream, only by employing the bit stream conversion (refer to Japanese Patent Laid-Open No. 2000-165879). However, the present inventor found a problem that the number of quantization steps may be sometimes extended to implement a compression method which is capable of such bit stream conversion, in which case the conventional compression method can not be employed.